How did you go about measuring the output
at different altitudes? Did you actually have wires running to some sort
of ohmmeter while in flight? Or did you use a pressure
chamber? If pressure (vacuum) chamber did you have a separate
vacuum source on the manifold lines? Otherwise, you would not have simulated
altitude accurately.
David;
What I
said:
“. . . even though
the measured output from the A and B sensors are the same when the unit is
powered up (out of the plane) at different altitudes (measured at 1400’ and
5300’).”
was not very
clear. The output measured at Ramona (1400’) was consistent; and that
measured at Boulder,
CO (5300’) was also –
within less than a milivolt. So this would suggest that the output
response is the same, or IOW, at WOT,
at different altitudes, A and B should be the same. The sensor on A
also appeared to be in fine shape in all respects. It is true that this
is not the same as pulling a
vacuum on the ports to say, 20” Hg with both at the same altitude.
That test seemed more difficult than buying a new sensor. I should know
next week whether that solves the problem.
In replacing the
sensor, and further studying the circuit, my son says “ I
installed the new MAP sensor, and
added a ground lead from the sensor to the processor (I think the lack of a
good ground return
was the source of the RF and
other problems). He has
remarked before that his opinion is that the ground circuits on the board are
not particularly resistant to RF issues.